// Copyright 2015 The BoringSSL Authors

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#ifndef OPENSSL_HEADER_CRYPTO_FIPSMODULE_RAND_INTERNAL_H

#define OPENSSL_HEADER_CRYPTO_FIPSMODULE_RAND_INTERNAL_H

#include <openssl/aes.h>

#include <openssl/ctrdrbg.h>

#include "../../bcm_support.h"

#include "../aes/internal.h"

BSSL_NAMESPACE_BEGIN

// rand_fork_unsafe_buffering_enabled returns whether fork-unsafe buffering has

// been enabled via `RAND_enable_fork_unsafe_buffering`.

int rand_fork_unsafe_buffering_enabled();

BSSL_NAMESPACE_END

// CTR_DRBG_STATE contains the state of a CTR_DRBG based on AES-256. See SP

// 800-90Ar1.

struct ctr_drbg_state_st {

  AES_KEY ks;

  bssl::block128_f block;

  bssl::ctr128_f ctr;

  uint8_t counter[16];

  uint64_t reseed_counter;

  int df;

};

BSSL_NAMESPACE_BEGIN

// CTR_DRBG_init initialises `*drbg` given `entropy_len` bytes of entropy in

// `entropy` and, optionally, a personalization string up to

// `CTR_DRBG_SEED_LEN` bytes in length. It returns one on success and zero on

// error.

//

// If `df` is false then `entropy_len` must be `CTR_DRBG_ENTROPY_LEN` and

// `nonce` must be nullptr.

OPENSSL_EXPORT int CTR_DRBG_init(CTR_DRBG_STATE *drbg, int df,

                                 const uint8_t *entropy, size_t entropy_len,

                                 const uint8_t nonce[CTR_DRBG_NONCE_LEN],

                                 const uint8_t *personalization,

                                 size_t personalization_len);

// BSSL_ENTROPY_DAEMON_RESPONSE_LEN is the number of bytes that the Android

// entropy daemon replies with.

#define BSSL_ENTROPY_DAEMON_RESPONSE_LEN (48 * 10 + 16)

// bssl_get_seed_from_daemon fetches up to `*inout_entropy_len` bytes of

// entropy from the Android entropy daemon, writing them to `*out_entropy`.

// On successful exit, `*inout_entropy_len` contains the number of bytes

// written. Returns one on success and zero on error.

int bssl_get_seed_from_daemon(uint8_t *out_entropy, size_t *inout_entropy_len);

#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM)

inline int have_rdrand() { return CRYPTO_is_RDRAND_capable(); }

// have_fast_rdrand returns true if RDRAND is supported and it's reasonably

// fast. Concretely the latter is defined by whether the chip is Intel (fast) or

// not (assumed slow).

inline int have_fast_rdrand() {

  return CRYPTO_is_RDRAND_capable() && CRYPTO_is_intel_cpu();

}

// CRYPTO_rdrand writes eight bytes of random data from the hardware RNG to

// `out`. It returns one on success or zero on hardware failure.

extern "C" int CRYPTO_rdrand(uint8_t out[8]);

// CRYPTO_rdrand_multiple8_buf fills `len` bytes at `buf` with random data from

// the hardware RNG. The `len` argument must be a multiple of eight. It returns

// one on success and zero on hardware failure.

extern "C" int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len);

#else  // OPENSSL_X86_64 && !OPENSSL_NO_ASM

inline int have_rdrand() { return 0; }

inline int have_fast_rdrand() { return 0; }

#endif  // OPENSSL_X86_64 && !OPENSSL_NO_ASM

BSSL_NAMESPACE_END

#endif  // OPENSSL_HEADER_CRYPTO_FIPSMODULE_RAND_INTERNAL_H